1. Field of the Invention
In some embodiments this invention relates to implantable medical devices, their manufacture, and methods of use. Some embodiments are directed to delivery systems, such as catheter systems of all types, which are utilized in the delivery of such devices.
2. Description of the Related Art
Balloon catheters are employed in a variety of medical procedures. One such procedure is angioplasty which is a well known medical practice used in the treatment of diseased arteries in the vasculature of a patient. Using angioplasty procedures, alone, however, involves a risk of restenosis of the artery, which may necessitate another angioplasty procedure, a surgical bypass procedure, or some method of repairing or strengthening the area. Therefore, it has become more common practice to use a catheter-delivered stent to prevent restenosis and to reinforce and strengthen weakened vessel walls.
A stent is a medical device introduced to a body lumen and is well known in the art. Stents, grafts, stent-grafts, vena cava filters, expandable frameworks, and similar implantable medical devices, collectively referred to hereinafter as stents, are radially expandable endoprostheses which are typically intravascular implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Typically, a stent is implanted in a blood vessel at the site of a stenosis or aneurysm endoluminally, i.e. by so-called “minimally invasive techniques” in which the stent in a radially reduced configuration, optionally restrained in a radially compressed configuration by a sheath and/or catheter, is delivered by a stent delivery system or “introducer” to the site where it is required. The introducer may enter the body from an access location outside the body, such as through the patient's skin, or by a “cut down” technique in which the entry blood vessel is exposed by minor surgical means.
After being introduced percutaneously, stents can be expanded by an internal radial force, such as when mounted on an inflatable balloon. Stents can also be self-expanding or a combination of self-expanding and balloon expandable (hybrid expandable). Stents may be implanted to prevent restenosis following angioplasty in the vascular system. Stents may be expanded and implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc.
A number of complications arise when stenoses form at vessel bifurcation sites. A bifurcation site is an area of the vasculature or other portion of the body where a first (or parent) vessel is bifurcated into two or more branch vessels. Where a stenotic lesion or lesions form at such a bifurcation, the lesion(s) can affect only one of the vessels (i.e., either of the branch vessels of the parent vessel) two of the vessels, or all three vessels. One complication involves irregular folding of the balloon or balloon portion which pushes against and moves that portion of the stent which expands into the vessel bifurcation. While auxiliary portions of a delivery system have been successful in expanding portions of stents into a side branch vessel, there remains a need for devices that are particularly suitable for expanding stents at a bifurcation to achieve an ideal expanded configuration.
The art referred to and/or described above is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.